Exploring dysfunctional barrier phenotypes associated with glaucoma using a human pluripotent stem cell-based model of the neurovascular unit.

Glaucoma is a neurodegenerative disease that results in the degeneration of retinal ganglion cells (RGCs) and subsequent loss of vision. While RGCs are the primary cell type affected in glaucoma, neighboring cell types selectively modulate RGCs to maintain overall homeostasis. Among these neighboring cell types, astrocytes, microvascular endothelial cells (MVECs), and pericytes coordinate with neurons to form the neurovascular unit that provides a physical barrier to limit the passage of toxic materials from the blood into neural tissue.

Induction of astrocyte reactivity promotes neurodegeneration in human pluripotent stem cell models.

Reactive astrocytes are known to exert detrimental effects upon neurons in several neurodegenerative diseases, yet our understanding of how astrocytes promote neurotoxicity remains incomplete, especially in human systems. In this study, we leveraged human pluripotent stem cell (hPSC) models to examine how reactivity alters astrocyte function and mediates neurodegeneration. hPSC-derived astrocytes were induced to a reactive phenotype, at which point they exhibited a hypertrophic profile and increased complement C3 expression.

A human pluripotent stem cell-derived in vitro model of the blood-brain barrier in cerebral malaria.

Background: Blood-brain barrier (BBB) disruption is a central feature of cerebral malaria (CM), a severe complication of Plasmodium falciparum (Pf) infections. In CM, sequestration of Pf-infected red blood cells (Pf-iRBCs) to brain endothelial cells combined with inflammation, hemolysis, microvasculature obstruction and endothelial dysfunction mediates BBB disruption, resulting in severe neurologic symptoms including coma and seizures, potentially leading to death or long-term sequelae. In vitro models have advanced our knowledge of CM-mediated BBB disruption, but their physiological relevance remains uncertain.

EVALUATION OF TRANEXAMIC ACID AND CALCIUM CHLORIDE IN MAJOR TRAUMAS IN A PREHOSPITAL SETTING: A NARRATIVE REVIEW.

Excessive blood loss in the prehospital setting poses a significant challenge and is one of the leading causes of death in the United States. In response, emergency medical services (EMS) have increasingly adopted the use of tranexamic acid (TXA) and calcium chloride (CaCl 2 ) as therapeutic interventions for hemorrhagic traumas. Tranexamic acid functions by inhibiting plasmin formation and restoring hemostatic balance, while calcium plays a pivotal role in the coagulation cascade, facilitating the conversion of factor X to factor Xa and prothrombin to thrombin.

The Effects of Propofol on a Human Blood-Brain Barrier Model.

Background: Recently, the safety of repeated and lengthy anesthesia administration has been called into question, a subset of these animal studies demonstrated that anesthetics induced blood-brain barrier (BBB) dysfunction. The BBB is critical in protecting the brain parenchyma from the surrounding micro-vasculature. BBB breakdown and dysfunction has been observed in several neurodegenerative diseases and may contribute to both the initiation and the progression of the disease.

Wnt signaling mediates acquisition of blood-brain barrier properties in naïve endothelium derived from human pluripotent stem cells.

Endothelial cells (ECs) in the central nervous system (CNS) acquire their specialized blood-brain barrier (BBB) properties in response to extrinsic signals, with Wnt/β-catenin signaling coordinating multiple aspects of this process. Our knowledge of CNS EC development has been advanced largely by animal models, and human pluripotent stem cells (hPSCs) offer the opportunity to examine BBB development in an in vitro human system. Here, we show that activation of Wnt signaling in hPSC-derived naïve endothelial progenitors, but not in matured ECs, leads to robust acquisition of canonical BBB phenotypes including expression of GLUT-1, increased claudin-5, decreased PLVAP, and decreased permeability.

Antibody screening using a human iPSC-based blood-brain barrier model identifies antibodies that accumulate in the CNS.

Drug delivery across the blood-brain barrier (BBB) remains a significant obstacle for the development of neurological disease therapies. The low penetration of blood-borne therapeutics into the brain can oftentimes be attributed to the restrictive nature of the brain microvascular endothelial cells (BMECs) that comprise the BBB. One strategy beginning to be successfully leveraged is the use of endogenous receptor-mediated transcytosis (RMT) systems as a means to shuttle a targeted therapeutic into the brain.

Correction to: An isogenic neurovascular unit model comprised of human induced pluripotent stem cell-derived brain microvascular endothelial cells, pericytes, astrocytes, and neurons.

Following publication of the original article [1], the author has reported that in Figure 1 (b and c) the y-axis TEER (© x cm) should be replaced with TEER (Ω x cm).

An isogenic neurovascular unit model comprised of human induced pluripotent stem cell-derived brain microvascular endothelial cells, pericytes, astrocytes, and neurons.

Background: Brain microvascular endothelial cells (BMECs) astrocytes, neurons, and pericytes form the neurovascular unit (NVU). Interactions with NVU cells endow BMECs with extremely tight barriers via the expression of tight junction proteins, a host of active efflux and nutrient transporters, and reduced transcellular transport. To recreate the BMEC-enhancing functions of NVU cells, we combined BMECs, astrocytes, neurons, and brain pericyte-like cells.

Regionally specified human pluripotent stem cell-derived astrocytes exhibit different molecular signatures and functional properties.

Astrocytes display diverse morphologies in different regions of the central nervous system. Whether astrocyte diversity is attributable to developmental processes and bears functional consequences, especially in humans, is unknown. RNA-seq of human pluripotent stem cell-derived regional astrocytes revealed distinct transcript profiles, suggesting differential functional properties.

Human pluripotent stem cell-derived brain pericyte-like cells induce blood-brain barrier properties.

Brain pericytes play important roles in the formation and maintenance of the neurovascular unit (NVU), and their dysfunction has been implicated in central nervous system disorders. While human pluripotent stem cells (hPSCs) have been used to model other NVU cell types, including brain microvascular endothelial cells (BMECs), astrocytes, and neurons, hPSC-derived brain pericyte-like cells have not been integrated into these models. In this study, we generated neural crest stem cells (NCSCs), the embryonic precursor to forebrain pericytes, from hPSCs and subsequently differentiated NCSCs to brain pericyte-like cells.

Studying Human Neurological Disorders Using Induced Pluripotent Stem Cells: From 2D Monolayer to 3D Organoid and Blood Brain Barrier Models.

Neurological disorders have emerged as a predominant healthcare concern in recent years due to their severe consequences on quality of life and prevalence throughout the world. Understanding the underlying mechanisms of these diseases and the interactions between different brain cell types is essential for the development of new therapeutics. Induced pluripotent stem cells (iPSCs) are invaluable tools for neurological disease modeling, as they have unlimited self-renewal and differentiation capacity.

Software to improve transfer and reproducibility of cell culture methods.

Cell culture is a vital component of laboratories throughout the scientific community, yet the absence of standardized protocols and documentation practice challenges laboratory efficiency and scientific reproducibility. We examined the effectiveness of a cloud-based software application, CultureTrax as a tool for standardizing and transferring a complex cell culture protocol. The software workflow and template were used to electronically format a cardiomyocyte differentiation protocol and share a digitally executable copy with a different lab user.

Directed differentiation of human pluripotent stem cells to blood-brain barrier endothelial cells.

The blood-brain barrier (BBB) is composed of specialized endothelial cells that are critical to neurological health. A key tool for understanding human BBB development and its role in neurological disease is a reliable and scalable source of functional brain microvascular endothelial cells (BMECs). Human pluripotent stem cells (hPSCs) can theoretically generate unlimited quantities of any cell lineage in vitro, including BMECs, for disease modeling, drug screening, and cell-based therapies.

An isogenic blood-brain barrier model comprising brain endothelial cells, astrocytes, and neurons derived from human induced pluripotent stem cells.

The blood-brain barrier (BBB) is critical in maintaining a physical and metabolic barrier between the blood and the brain. The BBB consists of brain microvascular endothelial cells (BMECs) that line the brain vasculature and combine with astrocytes, neurons and pericytes to form the neurovascular unit. We hypothesized that astrocytes and neurons generated from human-induced pluripotent stem cells (iPSCs) could induce BBB phenotypes in iPSC-derived BMECs, creating a robust multicellular human BBB model.

High Glucose Attenuates Anesthetic Cardioprotection in Stem-Cell-Derived Cardiomyocytes: The Role of Reactive Oxygen Species and Mitochondrial Fission.

Background: Hyperglycemia can blunt the cardioprotective effects of isoflurane in the setting of ischemia-reperfusion injury. Previous studies suggest that reactive oxygen species (ROS) and increased mitochondrial fission play a role in cardiomyocyte death during ischemia-reperfusion injury. To investigate the role of glucose concentration in ROS production and mitochondrial fission during ischemia-reperfusion (with and without anesthetic protection), we used the novel platform of human-induced pluripotent stem-cell (iPSC)-derived cardiomyocytes (CMs).

Differentiation and characterization of human pluripotent stem cell-derived brain microvascular endothelial cells.

The blood-brain barrier (BBB) is a critical component of the central nervous system (CNS) that regulates the flux of material between the blood and the brain. Because of its barrier properties, the BBB creates a bottleneck to CNS drug delivery. Human in vitro BBB models offer a potential tool to screen pharmaceutical libraries for CNS penetration as well as for BBB modulators in development and disease, yet primary and immortalized models respectively lack scalability and robust phenotypes.

Chemically-defined albumin-free differentiation of human pluripotent stem cells to endothelial progenitor cells.

Human pluripotent stem cell (hPSC)-derived endothelial cells and their progenitors are important for vascular research and therapeutic revascularization. Here, we report a completely defined endothelial progenitor differentiation platform that uses a minimalistic medium consisting of Dulbecco's modified eagle medium and ascorbic acid, lacking of albumin and growth factors. Following hPSC treatment with a GSK-3β inhibitor and culture in this medium, this protocol generates more than 30% multipotent CD34+ CD31+ endothelial progenitors that can be purified to >95% CD34+ cells via magnetic activated cell sorting (MACS).

Exploring the effects of cell seeding density on the differentiation of human pluripotent stem cells to brain microvascular endothelial cells.

Background: Brain microvascular-like endothelial cells (BMECs) derived from human pluripotent stem cells (hPSCs) have significant promise as tools for drug screening and studying the structure and function of the BBB in health and disease. The density of hPSCs is a key factor in regulating cell fate and yield during differentiation. Prior reports of hPSC differentiation to BMECs have seeded hPSCs in aggregates, leading to non-uniform cell densities that may result in differentiation heterogeneity.

Cdk1, PKCδ and calcineurin-mediated Drp1 pathway contributes to mitochondrial fission-induced cardiomyocyte death.

Myocardial ischemia-reperfusion (I/R) injury is one of the leading causes of death and disability worldwide. Mitochondrial fission has been shown to be involved in cardiomyocyte death. However, molecular machinery involved in mitochondrial fission during I/R injury has not yet been completely understood.

Concise review: tissue-specific microvascular endothelial cells derived from human pluripotent stem cells.

Accumulating evidence suggests that endothelial cells (ECs) display significant heterogeneity across tissue types, playing an important role in tissue regeneration and homeostasis. Recent work demonstrating the derivation of tissue-specific microvascular endothelial cells (TS-MVECs) from human pluripotent stem cells (hPSCs) has ignited the potential to generate tissue-specific models which may be applied to regenerative medicine and in vitro modeling applications. Here, we review techniques by which hPSC-derived TS-MVECs have been made to date and discuss how current hPSC-EC differentiation protocols may be directed toward tissue-specific fates.

Marked hyperglycemia attenuates anesthetic preconditioning in human-induced pluripotent stem cell-derived cardiomyocytes.

Introduction: Anesthetic preconditioning protects cardiomyocytes from oxidative stress-induced injury, but it is ineffective in patients with diabetes mellitus. To address the role of hyperglycemia in the inability of diabetic individuals to be preconditioned, we used human cardiomyocytes differentiated from induced pluripotent stem cells generated from patients with or without type 2 diabetes mellitus (DM-iPSC- and N-iPSC-CMs, respectively) to investigate the efficacy of preconditioning in varying glucose conditions (5, 11, and 25 mM).

Methods: Induced pluripotent stem cells were induced to generate cardiomyocytes by directed differentiation.